Как насчет UNION
?
SELECT field1, field2, field3, field4, field5, field6
FROM table WHERE field2 = "AA" AND field3 LIKE '%BBB%'
UNION
SELECT field1, field2, field3, field4, field5, field6
FROM table WHERE field2 = "AA" AND field3 LIKE '%CCC%';
Обновление
Упрощение по вашему запросу:
SELECT field1, field2, field3, field4, field5, field6
FROM table WHERE field2 = "AA" AND (field3 LIKE '%BBB%' OR field3 LIKE '%CCC%')